Leak at Minnesota Power plant has spilled 5.5 million gallons of coal ash wastewater

A leak at a Minnesota Power plant in Cohasset is now estimated to have released more than five million gallons of coal ash wastewater.

On Friday, Minnesota Power released an update on the Tuesday spill at its Boswell Energy Center. An underground break had resulted in wastewater making its way into Blackwater Lake, which feeds into the Mississippi River.

While Minnesota Power had originally estimated that one million gallons of wastewater had been released, it now says that number is 5.5 million gallons.

The Minnesota Pollution Control Agency is currently investigating the impacts of the leak. As of Friday, sulfate levels in the area were above drinking water standards, but acceptable for wild rice.

MPCA also hired a contractor to monitor contamination levels in the area. Preliminary sampling shows increased levels of sulfate and boron in the immediate area, according to the update.

Cohasset does not get its drinking water from the Mississippi River, according to the Star Tribune. Steve Robertson, assistant manager of the Minnesota Department of Health's Drinking Water Protection section, told the publication that the risk to local drinking water is low.

Minnesota Power, the largest utility company in northern Minnesota, intends to retire its two coal plants at the Boswell Energy Center over the next decade, with the first plant set to close in 2030 and the second in 2035, amid a shift to renewable energy.

But after the spill, environmental group the Sierra Club has called on the company to hasten the closures, calling on both to be shut down by 2030.

"Minnesota Power must take steps to ensure something like this doesn’t happen again, starting with a commitment to retire all of its coal generation by 2030 at the latest," it said in a statement. "There is no safe way to burn fossil fuels. Pipes leak, break, and spill, impacting our water, environment, and public health. Investing in electric generation that relies on unsafe infrastructure is dangerous to all of us."